my %accounts = (
  tom => "BigApple",
  tom2 => "BigApple2",
  tom3 => "BigApple3",
  tom4 => "BigApple4",
  tom5 => "BigApple5",
  tom6 => "BigApple6",
  tom7 => "BigApple7",
);
# sort the users in descending order
my $counter = 1;
for my $userID (reverse sort keys %accounts) {
  print "$userID\t";
  print "\n" if $counter++ % 3 == 0;
}

tom7    tom6    tom5    
tom4    tom3    tom2    
tom
[download]

You can avoid mucking about with counters and stuff by making the implicit list in the for loop an explicit array then splice chunks off it:

#!/usr/bin/perl
use warnings;
use strict;

my %accounts = (
  tom => "BigApple",
  tom2 => "BigApple2",
  tom3 => "BigApple3",
  tom4 => "BigApple4",
  tom5 => "BigApple5",
  tom6 => "BigApple6",
  tom7 => "BigApple7",
);
my @keys = reverse sort keys %accounts;

print join ("\t", @$_), "\n" while @$_ = splice @keys, 0, 3;
[download]

Prints:

tom7    tom6    tom5
tom4    tom3    tom2
tom
[download]

Premature optimization is the root of all job security

I received this message: Argument "t" isn't numeric le (<=) at c:\users\michael\desktop\lab7-startup.pl line 119, <STDIN> line 17. Any idea why?

I received this message: Argument "t" isn't numeric le (<=) ... Any idea why?

Because you've mis-copy/pasted the code. I can copy/paste the exact code posted by bangor above and run it with warnings and strict enabled, and no complaint from Perl.

---

Give a man a fish:  <%-{-{-{-<

He's a monk, not a clairvoyant!

Please post the relevant line of code that the error is pointing you to :-)



The way forward always starts with a minimal test.

Your program doesn't compile as posted. You have an undeclared variable in there.

Your main problem is that you have nested for loops that cause the program to print each name the number of times there are items in the list. You need to consolidate the two things you are doing in loops so that you only loop through the names once, using the same loop for your counter.

Hope this helps!

I made a few mods that you might find instructive. And added an undocumented option 6. Add a few accounts and see what that does!

#!/usr/bin/perl -W
use strict;
use 5.010;
use Data::Dumper;

my $heading = <<HEAD;
A script that allows a user to perform system administration tasks 
Programmer name:          Michael A. Gregor
Course:                   COSC 146
Lab#:                     7
Due Date:                 3/10/16
lab7.pl

HEAD
print $heading;

my %passwords = (tom => "BigApple");
my %types     = (tom => "admin");

my $menu = <<MENU;

         System Administration Tasks

1- Create a new account
2- Delete an account
3- Change an account password
4- List users in alphabetical order 
5- Exit the system

MENU


while (print $menu) 
{
    my $choice = prompt4input ("Make your choice: ");
    
    if ($choice == 1) {createAccount();  next;}
    if ($choice == 2) {deleteAccount();  next;}
    if ($choice == 3) {changePassword(); next;}
    if ($choice == 4) {listUsers();      next;}
    if ($choice == 5) {print "Good-bye!";exit(0);}
    if ($choice == 6) {print Dumper (\%passwords);
                       print Dumper (\%types); next;}
    
    print ("Bad Choice...Try Again!\n");
}

sub prompt4input  #returns response to a prompt string
{
   my $prompt = shift;
   
   print $prompt;
   my $input = <STDIN>;
   $input =~ s/^\s*//;  #remove leading  whitespace
   $input =~ s/\s*$//;  #remove trailing whitespace
   
   return $input;
}   

sub createAccount
{
    print "Creating Account...\n";
    my $userID   = prompt4input ("Enter your userID: ");
    my $password = prompt4input ("Enter your password: ");
    
    if (exists $passwords{$userID}) 
    {
       print "Error: Duplicate user id: $userID ";
       return;  #### update added
    }
    
    my $account_type;
    while ($account_type = prompt4input(
           "Enter the account type, admin (or regular): "),
           $account_type !~ /admin|regular/)
    {
        
       $passwords{$userID} = $password;
       $types{$userID}     = $account_type;    
    }
    print "Account for \'$userID\' was successfully created \n";
}

sub deleteAccount
{
    my $userID   = prompt4input ("Enter your userID: ");
    my $password = prompt4input ("Enter your password: ");
    
    if ($passwords{$userID} != "$password")
    {
        print "invalid user id/password combination!\n";
        return;
    }
    
    if ($types{$userID} != "admin")
    {
        print "$userID is not an admin...can not delete!\n";
        return;
    }
    delete $passwords{$userID};
    delete $types{$userID};
}

sub changePassword
{
    my $userID   = prompt4input ("Enter your userID: ");
    my $password = prompt4input ("Enter your password: ");
    
    if ($passwords{$userID} != "$password")
    {
        print "invalid user id/password combination!\n";
        return;
    }
    my $newPassword = prompt4input ("Enter new password: ");
    $passwords{$userID} = $newPassword;
}

sub listUsers
{
     # sort the users in descending order
     my $counter = 1;
     for my $userID (reverse sort keys %passwords) 
     {
         print "$userID\t";
         print "\n" if $counter++ % 3 == 0;  #divisible by 3 evenly
     }
     print "\n";
}
[download]

Below is my entire script, the problem I have is with Choice number 4.

ok, copy/paste your program, delete everything except "choice 4" and whats needed to run that portion, it shouldn't take long, and then your question code will be less than 20 lines

Also, you have too much copy/paste, you need more subroutines

I cut the code down to choice 1 and choice 4. I need choice 1 because you are suppose to be add userIDs and passwords. Choice 4 is suppose to be able to print those userIDs in descending order.

Hi MikeyG,

I don't think the anonymonk was suggesting to edit your OP. For one thing, it's better to leave them alone for history (ie other posts may refer to text that is then removed...), and for another, it was useful to see your whole script. Also, you introduced a syntax error when cutting code out, so what's left no longer compiles, as your original script did.

I think the anonymonk was suggesting to create a Short, Self-Contained, Compilable Example, which eliminates all but the essential code to show your problem. Mind you it should compile and run. In your case you could have shown code with just your sub for question number 4, providing the test data in a hash. Then the monks would have only had a dozen lines of code to review, and you would get help more easily. (Edit: much as in the example bangor showed you.)

As an added bonus, creating a SSCCE is very closely related to debugging and often the process of doing it will lead you to the answer yourself.

The way forward always starts with a minimal test.